| The relationship between phoria and the ratio of convergence peak velocity to divergence peak velocity. | |
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MedLine Citation:
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PMID: 20335602 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: The purpose of this study was to investigate the relationship between phoria and the dynamics of vergence eye movements as described by the ratio of convergence average peak velocity to divergence average peak velocity, termed the vergence peak velocity ratio. METHODS: Phoria and vergence step responses were recorded. Three measures of phoria were assessed: baseline phoria, which is the initial phoria measurement; adapted phoria, which is the phoria measured after a visual task; and change in phoria, which is defined as adapted phoria minus baseline phoria. Phoria was modified in two experiments: vergence steps located at different initial positions and different sustained convergent fixations. Four linear regression analyses were conducted to study the interactions among baseline phoria and vergence peak velocity ratio, adapted phoria and vergence peak velocity ratio, baseline and adapted phoria, and baseline phoria and change in phoria. RESULTS: Baseline and adapted phoria were significantly correlated to vergence peak velocity ratio. Adapted phoria and baseline phoria were also significantly correlated. The change in phoria induced by the vergence steps or a sustained fixation task was independent of the baseline phoria. CONCLUSIONS: These data support that phoria is a factor in the asymmetry between peak velocity of convergence and divergence and that baseline phoria level is not a factor in the amount of change observed in phoria level (adapted phoria minus baseline phoria). Future oculomotor models of vergence should incorporate phoria within the design. |
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Authors:
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Eun H Kim; Bérangère Granger-Donetti; Vincent R Vicci; Tara L Alvarez |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. Date: 2010-03-24 |
Journal Detail:
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Title: Investigative ophthalmology & visual science Volume: 51 ISSN: 1552-5783 ISO Abbreviation: Invest. Ophthalmol. Vis. Sci. Publication Date: 2010 Aug |
Date Detail:
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Created Date: 2010-07-23 Completed Date: 2010-08-20 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7703701 Medline TA: Invest Ophthalmol Vis Sci Country: United States |
Other Details:
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Languages: eng Pagination: 4017-27 Citation Subset: IM |
Affiliation:
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Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Convergence, Ocular / physiology* Eye Movements / physiology* Female Humans Male Strabismus / physiopathology* Vision, Binocular / physiology Young Adult |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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